Not "Yt" because that is already "Yttrium". God.
Discovered by Marie Curie, published July 1999.
Discovered by Marie Curie when she noticed that there was some yet unknown more radioactive element in their raw samples, after uranium and polonium, which she published 6 months prior, had already been separated. Published on December 1989 as: Section "Sur une nouvelle substance fortement radio-active, contenue dans la pechblende".
The uranium 238 decay chain is the main source of naturally occurring radium.
What a material:
- only exists in trace amounts in nature,but it can be produced at kilogram scale in breeder reactors
- it is only intentionally produced for one application, and one application only basically: nuclear weapons
Burning and Extinguishing Characteristics of Plutonium Metal Fires by RobPlonski
. Source. Commented by this dude: www.linkedin.com/in/robplonski/